What is flair?

Sorry for my ignorance, but I see a lot of people commenting "flair" as a description, but lomwkey I cannot understand? Anyone who care to expalin please

like mine is t1 flair (normally its prx and I have uk flag but I changed to sweden + t1 in memory of a user who died)
its the team you represent on your profile

Flair is the lil icon in front of your name indicating what team you support, like my flair is G2

when people say "flair", they're insulting the person's team who they said "flair" to, they mostly do this when the person has a bad take or something else